As a wear-resistant aluminum alloy for automobile parts, a hypereutectic aluminum-iron (Al—Fe) alloy containing from about 13.5 to about 18 wt %, or particularly about 12 wt % or greater of silicon (Si) and from about 2 to about 4 wt % of copper (Cu) has been generally used. Since such conventional hypereutectic Al—Fe alloy has a microstructure containing primary solid silicon (Si) particles, it may have improved wear resistance compared to mere Al—Fe alloys, and thus it may be generally used in vehicle parts which require wear resistance, such as shift forks, rear covers, swash plates, and the like.
An example of commercial alloys may include an R14 alloy (Ryobi Corporation, Japan), a K14 alloy, which is similar to the R14 alloy, and an A390 alloy which is used for monoblocks or aluminum liners.
However, since such hypereutectic alloys include a large amount of silicon (Si), their castability may be deteriorated; adjusting the size and the distribution of silicon particles may be difficult; and their impact resistance may be reduced. Furthermore, manufacturing cost may be higher than those of other aluminum alloys because they are specially-developed alloys.
Meanwhile, an Al—Sn alloy may be another example of self-lubricating aluminum alloy for vehicle parts. Since the Al—Sn alloy contains from about 8 to about 15 wt % of tin (Sn), self-lubricating tin (Sn) soft particles may be formed with microstructure, thereby reducing friction. Therefore, this Al—Sn alloy may be used as a base material for metal bearings used in high frictional contact interfaces. However, this Al—Sn alloy may have reduced strength of about 150 MPa or less, although the strength thereof may be enhanced by silicon (Si) content. Therefore, such Al—Sn alloy may not be used for structural parts of a vehicle.
The description provided above as a related art of the present invention is just merely for helping understanding of the background of the present invention and should not be construed as being included in the related art known by those skilled in the art.